lambda#to_proc.rb

class Proc
	def to_proc
		if lambda?
			takes = arity
			flexible = takes < 0
			required = flexible ? ~takes : takes
			proc do |*args, &block|
				args = args.size == 1 && Array === args[0] ? args[0] : args
				given = args.size
				if not flexible and given > required
					begin
						self.(*args, &block)
					rescue ArgumentError
						args = args.take(args.length - 1) if given > required
						retry
					end
				elsif given < required
					args[required - 1] = nil
					self.(*args, &block)
				else
					self.(*args, &block)
				end
			end.tap do |p|
				p.define_singleton_method(:arity){takes}
			end
		else
			self
		end
	end
end